Which Cable to Choose for Lawn Mowers
- 1. What is the difference between a cable and a wire
- 2. How to calculate cable cross-section
- 3. Which cable is better: copper or aluminum
- 4. Which cable is better: flexible or rigid
- 5. How to determine the quality of the cable yourself
- 6. What should be the insulation and sheath of the cable
- 7. The most popular cable brands:
- 8. Internet cable.
- 9. Computer cable.
- 10. TV cable.
- 11. Audio cable.
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1. What is the difference between a cable and a wire
Not such a naive question as it seems at first glance. So, according to building codes, from the Soviet era to the present, work with a cable is more expensive than with a wire.
But there was no sufficiently clear classification in this regard either under the USSR or now. Different reference books give different concepts. Even the most respected cablemaker reference, ed. Belorussova gives a very vague definition of cable, starting with the words: "the cable is called usually. " (i.E. Not always.) and very general concepts go on. In practice, the characteristic "cable" or "the wire" assigned by GOST or TU for the release of a particular brand.
So, GDP brand cable, developed by OJSC "Odescable" and the first to approve TU on it, differs from PVA brand wires only by the shape of the sheath: the GDP cable is flat, and the PVS wire. Round. At the same time, in no cable reference book the shape of the cable / wire sheath is at least a significant factor. So look at the certificate. There it will be surely said: a cable or a wire.
2. How to calculate cable cross-section
What section is the cable needed for, for example, 8kW? In the article How to calculate the cable cross-section, you can find out a detailed description of the calculation, but in practice most electricians use a simple formula: a copper cable cross-section of 1 mm 2 can pass 10A or 2.2 kW through itself (power = 10A x 220V). Thus, the load on 8kW in amperes will be 36A (load = 8kW / 220V), and for such an amount of current a cable with a section of 4mm 2 will be enough. This calculation is more. Less correct for cables with a cross-section of not more than 6 mm 2. For large cross-sections, tables are still needed "About permissible current loads". You also need to know that at the same load, the cross section of an aluminum cable should be about 30% more than copper.
Cable section. This is the area of the conductive core in the cut. The cross-section of a circular conductive cable core is calculated by the formula of the circle area = π × r 2, where the number π = 3,14, and r. Radius. If there are several delays in the vein. Then the core section will be equal to the sum of the sections of all wires. The radius of the wire is measured with a caliper, and very thin wires. Micrometer.
What margin of cross section is needed. Stock, of course, does not hurt. But you need to know the measure. So, any household switch sockets are designed for a maximum of 16A (3.2kW = 16A x 220V) and the connection of the outlet with a cable of 4 mm 2, with a capacity of 8 kW. It’s a waste of money. In addition, a cable with a cross section of 4 mm 2 does not fit into any outlet. Reasonable sections in household electrical networks for copper: 1.5-2.5 mm 2 for sockets and 0.75-1.5 mm 2 for lighting.
3. Which cable is better: copper or aluminum
Most "specialists" with deep conviction they will answer that copper. And let’s ask them. Why?
|Arguments for a copper cable||Counterarguments|
|copper is more durable||not true, open any cable directory and there you will see that the service life of copper and aluminum cable is exactly the same: 15 years. For cables in single insulation and 30 years. For cables in double insulation|
|copper does not break so quickly||it’s true. According to GOST, copper withstands 80 bends, and aluminum only 12, but it does not matter when laying the cable into the wall|
|aluminum oxidizes very quickly||indeed, an oxide layer is formed on top of freshly brushed aluminum in literally fractions of a second, which impairs contact. But oxidation does not occur beyond this layer and aluminum retains its conductive properties for many years along with copper. In addition, there is a modern solution to how to get good contact on an aluminum wire: a German company "Wago" produces terminal blocks with special paste. The conductive paste peels off the upper oxidized layer and seals the contact area from the penetration of water and air. It’s even better than a good copper twist|
|no more serious arguments?||And the counterarguments are also very significant: an aluminum cable is about 3 times cheaper than a copper cable of the same conductivity|
Conclusions: for the consumer, copper, compared with aluminum, is more profitable only because copper does not break so quickly with time, and this is very important when replacing lamps, sockets, etc. Is it worth it to pay 3 times more. The decision is yours.
On a note. Connect copper and aluminum cable only through the terminal block, so that aluminum does not come into contact with copper. The fact is that due to certain physical phenomena in the place where aluminum and copper come into contact with time, the current resistance increases. As a result, the connection site is very hot, the cable is destroyed, a short circuit occurs, and in the worst case. Fire. By the way, the connection of any dissimilar materials with different resistance leads to a similar effect. Therefore, it is not advisable to take the first wire that comes across and ground the wiring by twisting it. Depending on the field of application of the cable, the conductive core is made of various materials: primarily copper and aluminum, but there can be steel, nichrome, etc. If you are not sure of the uniformity of the material of the connected cables. Use terminal block.
4. Which cable is better: flexible or rigid
A rigid cable is usually understood to mean a cable with a single-conductor, and flexible. With multi-wire core. The more wires in the vein and the finer each wire. The more flexible the cable. In terms of flexibility, the cable is divided into seven classes: mono-conductor. This is 1st grade, and 7th grade is the most flexible. The higher the cable flexibility class. The more expensive it is.
Video: Which Cable to Choose for Lawn Mowers
Rigid cable is usually designed for sealing in walls and laying in the ground, and flexible. For connecting movable mechanisms or electrical appliances. In terms of operation, a rigid or flexible cable. Irrelevant. In terms of installation. Each electrician has his own preferences.
On a note: The ends of the flexible cable, which are inserted into sockets (switches), must be soldered or crimped with special terminators (tubular lugs). A hard cable does not require such a procedure. To connect the lighting equipment, it is preferable to take a flexible cable, since the lighting fixtures change more often, and the hard cable breaks faster when connecting new electrical equipment.
5. How to determine the quality of the cable yourself
There is also a cable with an understated sheath thickness or with a sheath made of low-quality material, which reduces the life of the cable. For verification, it is better to have a piece of the correct cable with you, as a reference, preferably from Soviet manufacture or familiarize yourself with the parameters of the type of cable you are interested in in the cable reference book, under the editorship of. Belarus.
In the Ukrainian markets you can find a Chinese cable made of aluminum coated with copper (sold as copper and has a Cyrillic mark). Such a cable is easy to check: a section of the conductive core on the cable shines white. Aluminum.
Some manufacturers use low-quality copper or aluminum to reduce costs. For such cables, the service life and conductivity of the core is significantly lower than in accordance with GOST. Check the quality of the metal of the conductive core as follows:
Try bending and straightening the cable several times. In factories, such a check is done on a special bending device under a certain bending radius. Therefore, your number of bends before breaking will most likely be less than stipulated by GOST. But in any case, aluminum must withstand at least 7-8 bends, and copper. 30-40;
A cable made of high-quality copper or aluminum should easily bend and not spring;
The copper or aluminum core on the cable that has just been stripped should have a bright (glare) color. If the vein is heterogeneous in color and has dark spots. It is not electrical copper (aluminum).
Nevertheless, the layman himself will not be able to fully determine the quality of the cable. In this case, one advice. Trust the brand. Today, standard high quality in Ukraine provides only one plant. "Odescable". The cable of this manufacturer always has the corresponding marking and the cable of the named factory is the most expensive everywhere. Of course, all Ukrainian factories can and do GOST cable not worse than Odessa. But they can also make other cables. From which in which case they will deny. And you cannot prove anything by legal methods. Everything has been worked out for a long time. European manufacturers present in Ukraine also offer standard quality cable. But the price is 1.5-2 times higher than our analogues and, moreover, you can get fake (there are cables with a Latin font supposedly made in Europe, but with a clearly underestimated cross-section of the core).
6. What should be the insulation and sheath of the cable
Definitely better in double insulation. It is enough to say that a cable in single insulation has a service life of up to 15 years, and in double insulation. 30 years. In the technical literature, it is customary to separate the terms insulation and sheath. Insulation. This is a layer of dielectric material superimposed on a current-carrying core, and a sheath. These are all layers on top of the insulation. The sheath serves to protect the cable from mechanical, chemical, thermal and other influences.
A cable can have several layers of sheath made of various types of material: from steel to fiberglass. Here are some types of shell that you might find useful:
Heat-resistant cables for laying in hot rooms, such as in a sauna. As a rule, PTFE material is used, and fiberglass is on top. There are no special designations for such cables, i.E. If necessary, refer to directories or catalogs, where the indicator operating temperature must be indicated;
Flame retardant marked "ng". Means the ability to self-extinguish when a fire goes out, but not withstand high temperatures. Do not confuse with heat-resistant and fire-resistant cables;
If the cable brand has the designation FR (fireproof) and then E30, E90 or E120. Then this cable can "work" in an open flame, respectively, for 30, 90 or 120 minutes. ;
Cables with a polyethylene sheath can be laid both in the ground and in an open method, for example, along the walls of buildings;
Cables with insulation and sheath made of PVC (polyvinyl chloride) are intended for indoor wiring (under plaster) or in cable ducts.
7. The most popular cable brands:
PPV wire (copper), APPV (aluminum) in single insulation for laying inside the walls;
PVA cable (copper), GDP (copper) in double insulation for indoor installation;
Cable heat-resistant RKGM (copper). Up to 180 ° С, BPVL (tinned copper) – up to 250 ° С;
VVG cable (copper), AVVG cable (aluminum) for laying along the walls of houses and in the ground;
Runway cable (copper) submersible for laying in water;
Cable CCI (copper) telephone pair for laying in the ground;
Cable TRP (copper) telephone distribution for subscriber communications (connecting the telephone)
Cable "twisted pair" UTP, FTP for creating computer networks, connecting intercoms, etc .;
Signal wire "Alarm" for connecting intercoms, security and fire alarms, etc .;
Coaxial cable RG-6 for connecting televisions, antennas, video surveillance cameras.
8. Internet cable.
There is no such term. To transmit information, various information cables are used. If we talk about connecting to the Internet, then you should find out from your operator. What cable do you lay in the walls. And find out the brand of cable and the manufacturer, so that later you will not be told about the bad cable and the correspondingly low speed of the Internet. For example, Volya-cable (Kiev) lays for the Internet a regular television cable of the Finmark trademark. And such telephone operators as Ukrtelecom and Golden Telecom use a cable "twisted pair" or existing subscriber cable (so-called "noodles") to which your phone is connected. On the "allocated" the Internet. Fishing lines can lay optical cable.
9. Computer cable.
Not an exact term. Usually a cable is used to connect computers to each other and to the server "twisted pair"but other data cables may be used. Term "twisted pair" came from the USA. The technology of twisting two veins in a couple has been used in telephony since the middle of the last century. The merit of the Americans is that due to the precisely calculated pitch of the graft and the quality of the materials, the information transfer speed was much higher than that of a standard pair telephone cable. A twisted pair cable has a lot of types depending on the number of cores, the diameter of each core, the laying conditions, etc. Depending on the data transfer speed, twisted pair cable is divided into groups: category 3 (standard telephone cable), category 5 (used in office network devices), category 6 (new generation cable designed to replace category 5). Twisted pair, received the most widespread today. This is a category 5e cable from eight pairwise twisted cores, the diameter of each core is from 0.45mm to 0.51mm.
10. TV cable.
This is not an accurate (household) name for a 75 ohm coaxial cable. And a completely wrong term. "Satellite cable". Any 75 ohm coaxial cable can be used to connect a satellite and any other antenna, as well as to connect to cable television. The only important thing is a good cable or so-so. Key features of coaxial cable. This is signal attenuation and noise immunity. All other cable characteristics (screen density, wire material, etc.) are aimed at improving these two indicators and are of secondary importance. For example, a domestic RK cable is made only of copper wire (sometimes even silver plated), but the attenuation of the RK cable is 3-4 times worse than any modern RG cable made from cheaper materials: steel and aluminum. At the present stage, the quality of the information cable is determined primarily by technology. When choosing a television cable, also consult your service provider.
11. Audio cable.
There are music lovers who have absolutely breathtaking audio cables. With finger. There are experts who acquire a good sound "vacuum-copper"silver-plated and even gilded cables at prices from 20 to 100 per meter. In contrast, some experts argue that on the appropriate measuring equipment, the differences between the sound passed through a conventional copper conductor and the sound passed through "super cable", can not see. However, music lovers say that the difference is very much heard. If you are not a music lover. Then lay any copper cable in the wall (cheaper).
Interesting fact. Strictly speaking, Morse is not the inventor of the telegraph code: the so-called Morse code. Samuel Morse was an unsuccessful artist and for a long time was supported by his mother. The issue of coding and further decoding of signals in telegraph communication has been discussed among engineers for decades and the solution has already been "was in the air". It’s just that S. Morse patented a randomly overheard conversation on this subject. Morse generally patented everything that got horrible, but he was lucky only in the telegraphic alphabet. True, then he continued to defend his rights in the courts for another 30 years, which he did with the help of corruption that took place in the US Congress.
Attention: This is an author’s article, therefore, when using the material, please make a reference to the source.